The invention relates to a magnetic valve controlled fuel injector for a multi-cylinder internal combustion engine with direct fuel injection. The fuel injector includes in an injector housing a control piston and a valve body cooperating with the control piston. A high pressure line extends to the valve body and is, when the valve body is open, in communication with a fuel supply line which leads to a pressure chamber surrounding an injection nozzle valve needle. A passage extends through the control piston and the valve body by way of which a control space delimited by the control piston is constantly in communication with the high pressure line by way of a throttle structure. The pressure in the control space can be released by the magnetic valve to control the injection. A fuel return line is provided which also includes a throttle structure.
Such a magnetic valve controlled fuel injector is known from DE 196 12 738 A1, wherein the control piston with an integrated valve body is guided in two housing parts and has a backside which is in direct contact with the nozzle needle: the valve body is surrounded by an annular space to which a fuel admission line leads and to which also a throttled return line to a low pressure fuel storage is connected.
In this type of system, the high pressure line leading to the injection nozzle is pressure-relieved by the throttled return line, that is by the constant communication path between the supply line by way of the annular space and the low pressure return line.
It is the object of the present invention to provide a fuel injector with which, by inexpensive measures, the efficiency is substantially improved.